Stucked in world texture panel
You are in cycles render engine. The texture panel, and material panel are different in cycles than in Blender internal.

What you want, is the texture panel from Blender internal.

I'm sorry, but there's not way to get the Blender internal panel in cycles, and it would not be practical, as the renderers work in different ways. You could switch to Blender Internal, but Cycles has many superiorities, so if I were you, I would just use the new design, and get used to the way it works.

Keep in mind: You can switch which texture you are editing in Cycles, by clicking where it says "environment texture", and selecting another texture.